June 1, 2002
by Dr. Chris Miller and Dr. Shannon Mills
If I have experienced it once, I have experienced it a thousand times! I find myself boarding a plane casually watching others settle in, and then waiting for it to happen. It starts with just a few noises, perhaps from two or three people throughout the plane — a simple cough, a sneeze, followed by some sniffles. It is the sound associated with millions of microorganisms starting to fill the air.
To the untrained ear, these sounds are not even noticeable. Because I am a frequent traveler, my ear is tuned in as I listen to the various ailments of those surrounding me. As the door closes and time passes, I envision airborne pathogens building around me, almost like rising water with no way out. At that moment, I say to myself, “If I could only wear a mask right now,” because I know I am breathing in this stuff too!
Instead, I try to hold my breath, while the waves of unseen microorganisms pass me by. “It won’t work,” I rationalize. “We are stuck in this large metal box called an airplane! Oh, how I wish I knew the medical histories of my fellow passengers! It would make me feel a lot safer breathing in the shared air for the next few hours!”
Thinking back, I actually did try wearing a mask once on an airplane to put my plan into action. It took about 10 minutes for total humiliation! Alarmed passengers quickly passed by me as if to say, “Stay away from me!” Instantly, there was a fear of being infected with a contagious disease! Ironically, I was merely trying to protect myself from them!
Have you ever experienced this same scenario? Have you ever been in a situation where you wished you had some type of protection when you walked past someone who started to cough or suddenly sneezed? At that moment, you may share my feeling of vulnerability to potential droplets of infection.
While it may not be socially acceptable to wear a protective mask on an airplane, there is another location where it is accepted and even required! It is a place where all too often, personal protection procedures are not closely followed and where your own safety is often taken for granted. It is the dental operatory – or what may be called the perfect incubator! Take a moment to think about it. A typical area may be a 10’x10′ room with lots of moisture from numerous sources. It could be droplets of splatter from high-speed handpieces, ultrasonics, or merely the breath of numerous individuals filling the air throughout the day.
How many passengers (patients) board your dental plane per day? Twenty? Thirty? Maybe forty? What is the square footage of your total office area? How many days do you spend in your office? If you really stop to think about it, what are you doing to protect yourself in your daily life? Are you confident that your action plan to reduce cross-contamination is enough?
To find out, take a quick test — it’s really easy. Ask yourself the following questions related to your mask-wearing habits. Award yourself one point for each “yes” answer. Add up your total score. Here’s the bad news. If you have one point or more, you lose! The mask link in the barrier protection chain has been broken. (See sidebar on this page.)
So, how did you score for mask protection? What about other protective barriers? Think of additional questions for basic items such as gloves, glasses, or protective garments. Can you pass a test for them as well? Is it possible that, in your daily activities, you may be taking your own safety for granted?
As illustrated, it is easy to breach any area in maintaining your personal protection. The important concept is to identify and eliminate everyday activities that may contribute to breaking any link of infection control. Once the chain is broken, the door for potential risk is open for you and your patients.
Now, for the good news! According to the American Dental Association’s “Policy Statement on Bloodborne Pathogens, Infection Control, and The Practice of Dentistry,” the dental office is a safe place to provide and receive dental care. The policy further states there is no significant risk to the healthcare professional as long as appropriate infection control guidelines are followed (ADA House of Delegates, October 1999). Clearly, the ADA policy shows there is a tie between your personal safety and making sure the chain of infection control is not broken.
To serve as a benchmark, the concept of “universal precautions” was introduced by the Centers for Disease Control and Prevention (CDC). These required infection-control guidelines serve as a source for all healthcare workers. The CDC further introduced the primary principle behind the standards that all patients must be treated as potentially infectious. For optimal protection, it is therefore necessary that every link or aspect of infection control be adhered to at all times.
When applied to facial masks, with all the coughing, flu, and colds being passed around, combined with more serious airborne pathogens, do you adhere to the single easiest thing to do to protect yourself — change your mask between patients? It is so simple that we almost forget about it! Moreover, if you are generating high-speed aerosols, a generally accepted timeframe is to change your mask after 20 minutes! Even in a dry climate, experts recommend that a mask be changed after 60 minutes. How often do you change your mask?
In a recent interview with Dr. Chris Miller, executive associate dean and professor of Oral Microbiology at Indiana University, School of Dentistry, Dr. Miller described the reasons why maintaining proper mask protection is necessary.
Dr. Miller explained that many dental professionals believe masks are simply to protect oneself from breathing in or inhaling particles in the air. Beyond this basic understanding, the primary function of masks is to protect the professional from large splatter or droplets that may hit the mucous membranes of the nose and the lip or mouth area.
What a shift over the years! Gone are the days when a surgical facemask’s primary use was to ensure healing for the patient! Now, facial masks play an important role as a barrier for professional healthcare workers from potentially dangerous airborne pathogens found in droplets of splatter.
So what does time have to do with mask protection? Why is there concern about changing masks so frequently? Dr. Miller and other experts agree that once a mask is moistened, there is a wicking effect that occurs as moisture is drawn into the material. Direct contamination quickly results, making the mask ineffective as a protective barrier.
In reviewing the OSAP Infection Control Guidelines, they describe the wicking effect much like a vacuum cleaner sucking in all of the contamination. A logical conclusion would be that the less water absorbed by a mask, the better the mask in terms of fluid resistance. OSAP and the Food and Drug Administration (FDA) agree with this thought and recommend that surgical masks have a 95 percent filtration efficiency for particles 3-5 microns in diameter. They further require that a mask be worn whenever splash or splatter is anticipated. (OSAP, 1997)
Some experts say the recommended particle filtration range may be acceptable from 1 to 6 microns when determining the BFE — bacterial filtration efficiency — a term commonly used for testing facial masks. The American Society for Testing and Materials (ASTM) defines BFE as the “effectiveness of medical face mask material in preventing the passage of aerosolized bacteria; expressed in the percentage of a known quantity that does not pass the medical face mask material at a given aerosol flow rate” (ASTM Designation: F 2100 – 01).
What does all this mean in practical terms? In an interview with Dr. Shannon Mills, the chair of OSAP and the dental programs manager for the Air Force Medical Operations Agency, he explained that surgical masks do not offer reliable protection against true aerosols. These small particles may remain suspended in air for an extended period of time and can be drawn into the terminal alveoli of the lungs. Although there is no evidence that bloodborne pathogens are transmitted by aerosols, this is the manner in which tuberculosis is transmitted. In order to be protected from aerosols, healthcare workers must wear respirators that have been certified National Institute for Occupational Safety and Health (NIOSH). To be effective, these devices usually need to be tested by a trained technician to ensure a proper fit.
Fortunately, most of the material generated in dental procedures is in the form of larger particles including droplets and spatter that tend to drop out of the air over time. These larger particles are not carried into the lungs but can come in contact with the eyes or oral mucous membranes. Such exposures are capable of transmitting bloodborne pathogens such as hepatitis B.
Even if you are wearing a face shield rather than protective glasses, Dr. Mills recommends that you wear a mask to ensure barrier protection. Even though surgical masks may not provide total protection from aerosols, they prevent exposure to droplets and spatter and may also reduce the risk of inhalation of aerosols.
A practical timeframe for how long one should wear a facemask is simply when a mask is visibly splattered or soiled during a procedure, it is time to change your mask. An example not often thought of is visible splatter of blood caused by a prophy cup during a prophylaxis on a patient with advanced gingivitis or periodontal disease. In effect, this may present a high-risk procedure.
To summarize, Dr. Mills stated, “Although clearly a mask should provide some measure of protection, it acts primarily as a barrier for mucous membrane exposure by droplets or splatter.”
It seems rather simple: Remembering to change your mask between patients will greatly reduce your potential exposure to hazard. This practical step applies to the medical and hospital community as well. According to the standard precaution guidelines from the Hospital Infection Control Practice Action Committee (HICPAC), coughing and sneezing are examples included in the list of hazardous droplet transmission sources. Essentially, what may seem like an innocent cough or sneeze could end up compromising anyone’s safety — perhaps in any environment or setting.
A final thought — The next time someone beside you sneezes, will you be tempted to say: “Bless you. Would you please pass me your medical records?”
Perhaps it may not be necessary in a dental operatory if you use proper barrier protection, however, you may want to think twice when you travel on an airplane!
Dr. Miller is executive associate dean and professor of Oral Microbiology at Indiana University, School of Dentistry.
Dr. Shannon Mills is the chair of OSAP and the dental programs manager for the Air Force Medical Operations Agency.
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